We propose to continue our studies on the relationship between the basic organic and biorganic chemistry of ozone and associated or suspected health effects. Our overall objective is to attempt to relate this basic ozone chemistry to observed or anticipated environmental health effects. Specific objectives include continuing our studies on the use of carbonyl oxides as models for the monoxygenase enzymes (MOX). We will continue to study the reactions between cabonyl oxides and selected polycyclic aromatic hydrocarbons. We will also extend our modeling studies to include additional substrates including sulfides (as models for cystine residues), ketones, and substituted phenols. The substrates will be chosen so as to further test the suitability of carbonyl oxides as MOX models. The methodology will include a continuation of our solution phase studies as well as gas phase analogs in order to move closely approximate environmental conditions. The studies will also require an extension of our work to determine the relative contributions of ozone versus carbonyl oxide oxidation. The relationship between ozone and carbonyl oxide chemistry and chemical carcinogenesis will be further investigated.